Spark plug



June 21 1927,

SPARK PLUG Filed Deo. 2a. 192:5

E. N. DEALCOc-ER ET Ag.

WITNESSES A TTORNE YS Patented June 21, 1927.

NITED STATES PATENT oFFICE.

EUGENIO DE ALCOCER AND FRANCISCO'O. DE ALCOCER, :0F MEXICO, MEXICO.

SPARK PLUG.

Application filed December 2s, 1923. ser1a1.No.sss,22s.

when one of the minor parts are broken or,A

rendered otherwise unfit for use.

As a further object the invention contemplates a spark plug which will increase the .eiiiciency' of the engine to which itis applied by means of its construction which reduces to a minimum the formation and collection of carbon and which prevents leakage through the plug and `consequent loss of compression.

As a still further object the. invention aims to provide a spark plugwhich is comparatively simple -in its construction,- inex.

pensive to manufacture and produce and AWhich is thoroughly reliable and highly ef-l ficient in its purpose.v

lVith the above recited and other objects in view, the invention resides in the novel construction set forthin' the following specification, particularly pointed out in the lappended claims and illustrated in Jthe accompanying drawings, it being understood that the rightis reserved to embodiments other than those actually illustrated herein to the' yfull extent indicated by the general 'meaning vof the terms in which the' claims are cylindrical shell or casing constituting a .part oi the body ofthe plug, the said shellor casing being providedk with areduced externally threaded boss 11 at its lower end providing at its juncture with the casing an external enlarged shoulder 12 whichlis bore 17.

removable drawings byv characters oi reference, 'designates a substantiallyv designed to seat against a packing ring 13 which is clamped against the cylinder head.

14 around the threadedopening which re- The shell or casing ceives the plug boss. 10 is provided with an external multifaced portion 15 which constitutes a means with which a wrench or other tool is engaged for screwing theplug into place on the vcylinder head. The plug, shellv or casing is provided with an upper enlarged bore 16 whichl communicates with a reduced lower bore 17 extending lthrough the hollow boss. The lower end of the bore 17 is flared outwardly as at 18 for a purpose to be hereafter set forth. At their juncturethe bores 16 and'17 provide an internal annular shoulder 19 u on which an insulator member 20 mounte in the bore 16 is adapted to seat at. its-lower end. The insulator member is preferably constructed of porcelain and is rovided Ywith a. reduced upper end 21 whlch protrudes fr'o'mtheupper end of the casing or shell y10. An annular gasket or packing .ring 22 is interposed between the lower end which a iange 25 is spun inwardly over the` shoulder 23'and gasket 24 to rigidly retain the insulatorV member 'in .juxta osition. The. insulator member lis provide atk its lower end with an extension or boss 26 which extends through the'gasket or packing ring and into the upper portion of the Thel insulator member is provided with an axially extending bore 27 from the upper .to the lower end. Adjacent the lower end the bore flares outwardly to provide ay conical seat28. The parts thus described constitute the body or carrier member of .the plug which serve as a means for attaching and supporting ythe electrodes to .be

hereinafter described in proper positionv on which extend axially thereoffand divide the head finto a plurality of clamping jaws 35. rl`he carried member further includes a frusto--conical insulating and filler member 36 which is provided with an axially extending conductor rstem 37 secured therein in any suitable manner against movement `and with its opposite ends projecting therefrom, the lower terminal 3S constituting an electrode. The upper terminal is pointed as at 39 to facilitate its insertion within the bore 33 of the head 32 which head in effect constiti'ites agripping chuck for coupling the upper vend of the stem 37 to the lstem 30 which is also of a conducting material. The lower end of the iiisulat-ing member 36 is encased in a shell 40 which is also of a` frusto-conical formation and is provided with yangular diametrically disposed downwardly inclined extensions 41 which are designed to constitute ground electrodes, the free ends of which are properly spaced from the central electrode 38 to constitute spark g'aPS.-

` In practice the stem 30 is inserted from the lower end of the plug whereby it extends upwardly through the bore 27 of the insulator member 2O with the threaded end pro truding above the saine and with the conical head defining the gripping fingers 35 arranged within the downwaidly and 0utvwardly flared portion 28 ofthe bore 27.

Preferably washers 42 surround the stem and rest upon vthe upper end 21 of the insulator member 2O after which a split washer 43 is arranged over the stem resting upon the upper end 21 of the insulator member 2O vafter which a split washer 43 is arranged over the stem resting upon the washers 42. A retaining nut 44 is then threaded on the end 31 and serves to effect axial movements of the stemv v31 and corresponding movements of rthohead 32 whereby upon upward movement of the stem the gripping lingers 35 are radially contracted, and upon downward movement radial expansion of the same is effected. il binding nut 45 is threaded on the upper end of the stem 31 which serves as a binding post forattaching the conduit wire of the ignition system to the plug.

Prior to the contraction of the gripping lingers 35 by upward movement of the stem A30 the insulator member 36vaiid its component parts are inserted in the flared lower end 18` of the bore 17 and the Ypointed terminal 39 of theV` stem 37 is inserted in t-he bore 33 of the head 32. By turning the securing nut 44 to effect upward movement of the stem 30v the gripping fingers 35 will radiallyvcontract about the upper end of the stem v37 and couple the same with the stem 301whereby the shell 40 is eectuall-y seated inthe flared portion 18 of the bore 17. The

lower end ofthe insulating member 36 is provided witha ,semnspherical recess 46 4which'constitutes a gas chamber communieating with the combustion ehambo' of the cylinder and which functions when the expansion takes place to dislodge from the ,Y

conical seat l18 and 'shell 4() and insulating member 3G will positively prevent the escape of pressure or loss of compression due to the fact that "the force exerted against the same will tend to more firmly seat the inembers 36 and 40 in place within the boss 11. In event of breakage or any other cause which requires the replacement of the electrodes of the porcelain member 36,' said section of the carried member may'be readily replaced at a nominal cost.

lVe claim V:

l. In a spark plug, the eombination'with the shell and insulator member, of a removable plug member fitted within and closing the lower end ofthe Vshell and carrying spaced central and grounded electrodes, and a stem extending through theinsulator member and detachably connected with the central electrode, said lstem and insulator member having interengageable portions for effecting the frictional coupling of the stem i adapted for detachable association with'the carrier member and, comprising apair of stem sectionshaving a means of connection coacting with the flared portion ofthe bore of the insulator element for rendering the connection active, an insulator head carried by the free end of one of the stem sections land providedv with spaced electrodes, said head coacting with the flared portion of the bore of the shell to close the same and to clamp the spacedelectrodes in groundedre'v lation to the shell and cylinder. 3 Y

3. In a spark plug,the` combination with ashellvand an insulator member, of' a removable closure plug member fitted vwithin the lower end of the shell and carrying spaced central and grounded electrodes, a stem extending through the insulator member having a radially contractable clamping portion for receiving the central electrode'A and interengageable portions onthe'stem and insulator member for setting up ,a clamping action of the stem about the portion of the central electrode which is received by the clamping portion, upon axial movement of ber.

4. In a spark plug, the combination with a shell and insulator member, vof a removable closure plug member' fitting closely within the lower end of the shell and carrying spaced central and grounded electrodes, the central electrode extending inwardly from the closure plug, a conductor stem extending through the insulator member having clamping means engageable with the inwardly extending` portion of the central electrode, the said insulator member and clamping means of the conductor stem having coacting faces adapted upon axial movement in one direction to effect clamping engagement of the stem and central electrode and the retention of the closure plug in engagement within the shell.

5. In a spark plug, a shell having an outwardly Haring lower end, an insulator member mounted in the shell having an axial bore provided with a fuiste-conical flaring lower end, a' substantially rusto-conical elosure plug memfber of insulating material snugly fitting within the lower end of the shell and having spaced central and grounded electrodes, the central electrode extendingupwardly from the closure plug into the enlarged lower end of the bore of the insulator member, al conductor stem positioned in the bore of the insulator member having an axially split frusto-conical lower end arranged in the lower end of the bore of the insulator member and provided with a bore receiving the upper end of the central electrode, and means threadedly engaging the upper end of the stem for drawing the same upwardly whereby to cause the lower frustoconical end of the stem to clamp the upper end of the central electrode and move the same upwardly therewith to snugly sit and retain the closure plug in the lower end of the shell.

, EUGENIO N. DE ALCOCER.

FRANCISCO O. DE ALCOCER. 

